Fragile negotiations between the United States and Iran were thrown into turmoil Sunday after President Donald Trump issued a series of threats against Tehran while senior officials from both countries were engaged in high-level peace talks in Switzerland.
The negotiations, held at the luxury Bürgenstock resort overlooking Lake Lucerne, were intended to launch a 60-day process aimed at resolving long-standing disputes between Washington and Tehran following the signing of an interim agreement earlier this month. Instead, the talks were overshadowed by Trump’s warnings that the United States could launch fresh military strikes against Iran if it failed to restrain Hezbollah militants in Lebanon.
In a series of posts on Truth Social, Trump demanded that Iran immediately stop what he described as Hezbollah’s efforts to create instability in Lebanon. He warned that failure to do so would trigger a stronger American military response than previous operations.
“If they do not, we will hit Iran harder than ever, just like we did last week — even harder,” Trump wrote.
The U.S. president also escalated his rhetoric regarding the Strait of Hormuz, the strategic waterway through which roughly one-fifth of the world’s oil and liquefied natural gas shipments normally pass.
Trump warned that if Iran attempted to shut down the strait, the consequences would be severe.
“You won’t even have a country to return to,” Trump said, suggesting the United States could take control of the waterway if necessary.
He further claimed the United States could serve as the “Guardian Angel” of the Strait of Hormuz and hinted at imposing fees on maritime traffic if no final agreement is reached with Tehran.
The remarks sparked immediate anger from the Iranian delegation, which was participating in talks alongside U.S. representatives, with Pakistan and Qatar acting as mediators.
According to Iran’s state news agency IRNA, Iranian negotiators temporarily left the negotiating venue shortly after Trump’s comments were published.
“The delegation of the Islamic Republic of Iran, after meeting with the Qatari delegation as one of the mediating parties, left the building where the negotiations were being held,” IRNA reported.
Iranian officials argued that Trump’s comments directly contradicted the spirit of the diplomatic process and undermined efforts to build trust between the two countries.
The departure created fresh uncertainty around negotiations that were already facing significant challenges because of continuing tensions in Lebanon and disagreements over key provisions of a future agreement.
However, diplomatic sources familiar with the talks said the situation remained fluid and that Iran had not formally withdrawn from the negotiating process.
One diplomat, speaking on condition of anonymity because of the sensitivity of the discussions, said Iranian negotiators remained engaged through intermediary channels and had not indicated a final decision to abandon the talks.
“Delegates remain involved in the process and have not informed mediators of any intention to terminate negotiations,” the diplomat said.
Trump’s comments came only hours after Vice President JD Vance struck a notably different tone at the opening of the talks.
Standing alongside senior U.S. negotiators Jared Kushner and Steve Witkoff, Vance described the gathering as an opportunity to transform relations across the Middle East.
“The question before us now is how much more can we accomplish together?” Vance said. “Can we turn over a new leaf? Can we permanently change relations in the Middle East? Or do we return to the old way of doing things?”
Despite those conciliatory remarks, the negotiations quickly became dominated by concerns over Trump’s threats and the deteriorating security situation in Lebanon.
Iranian Foreign Ministry spokesman Esmaeil Baghaei had already signaled before the meeting that progress toward a final agreement would depend heavily on developments in Lebanon.
“There can be no transition to final agreement negotiations unless the war in Lebanon ends,” Baghaei wrote on social media before the talks began.
The interim memorandum of understanding signed earlier this month included provisions aimed at ending hostilities between Israel and Hezbollah. Yet repeated outbreaks of violence since the agreement was reached have repeatedly threatened the broader diplomatic effort.
Although a renewed ceasefire appeared to be holding Sunday evening, Iranian officials continued to argue that Washington had failed to fully deliver on commitments related to regional de-escalation.
The tensions were further heightened by Iran’s recent decision to reimpose restrictions around the Strait of Hormuz following renewed Israeli military operations in Lebanon. Tehran maintains that its actions are linked to regional security concerns and what it describes as failures by the United States to enforce the terms of the ceasefire framework.
Iranian chief negotiator Mohammad Bagher Ghalibaf responded sharply to Trump’s latest remarks, warning Washington against further escalation.
“They should be careful with their words,” Ghalibaf wrote on X. “Our armed forces are prepared to respond in different ways.”
The exchange underscored the increasingly confrontational atmosphere surrounding negotiations that were supposed to focus on technical issues related to implementation of the interim agreement.
Iranian state television reported that nuclear matters were not discussed during the opening round of talks, which lasted approximately 80 minutes. Instead, negotiators concentrated on implementation mechanisms for the memorandum of understanding and the ongoing situation in Lebanon.
Iranian President Masoud Pezeshkian also reiterated Tehran’s position that it would not abandon its uranium enrichment program, while insisting that the country has no intention of developing nuclear weapons.
“We can state in writing that we do not intend to build a bomb,” Pezeshkian said. “But we will not give up our right to enrich uranium.”
The latest dispute highlights the fragility of the diplomatic process despite the breakthrough achieved earlier this month. The agreement reached between Washington and Tehran was widely viewed as a significant step toward reducing tensions that have dominated relations between the two countries for decades.
Yet Sunday’s developments demonstrated how quickly progress can be threatened by regional conflicts, domestic political pressures and inflammatory rhetoric from both sides.
As mediators from Qatar and Pakistan continued efforts to keep communication channels open, uncertainty remained over whether negotiators would be able to return to substantive discussions and maintain momentum toward a final agreement.
For now, the future of the peace process appears increasingly dependent not only on resolving disputes between Washington and Tehran, but also on preventing renewed violence in Lebanon from derailing one of the most ambitious diplomatic initiatives in the Middle East in recent years.
